glot.io lets you run and share snippets.
Snippets can be saved as either public or secret. Public snippets will show up in /snippets and will be found by search engines. Secret snippets can only be accessed by those who know the url.
Code is executed inside a temporary container without a network connection. Execution time is limited to 15 seconds and the output can not exceed 100KiB. Memory is limited to 500MB.
Ace is used as the code editor. Make sure to check out the leftmost and rightmost tabs, where you can select language version, set a custom run command and change the editor keybindings.
Are you missing your favorite library or language? Issues and pull requests are gladly accepted here.